Electrical contact assembly



Dec. 22, 1953 J. H. F. VAN WERD ET AL 2,663,853

ELECTRICAL CONTACT ASSEMBLY Filed April 13, 1950 H. J. NDE SO AGENT Patented Dec. 22, 1953 ELECTRICAL CONTACT ASSEMBLY Johannes Hendricus Franciscus van Werd and Charles Henri Joseph Anderson,

Eindhoven,

Netherlands, assignors to Hartford National Bank and Trust Comp trustee any, Hartford, Conn., as

Application April 13, 1950, Serial No. 155,600

Claims priority, application Netherlands April 22, 1949 2 Claims. (01. 339-210) The invention relates to an electrical apparatus comprising an insulating body enclosing an electrical contact assembly or junction unit. Such apparatus exist in widely different forms, for example in the form of contact plugs, switches, lampholders and so forth.

It is an object of the invention to provide a construction of an electrical supply contact which may be realized with the use of components readily obtainable commercially.

It is another object of the invention to provide an easily adjustable electrical contact for an electrical apparatus, such as a discharge tube.

In accordance with the invention, the supply contact comprses an assembly of an insulating body enclosing a screw member, the head of which member is recessed and is housed in a cavty provided in one of the internal walls of the insulating body. This head is made easily accessble to a tool manpulated from the outside of the insulating body through a passageway in the insulating materal. The opposing end of the stem of the screw member is preferably narrowed and not threaded. An electrcally conductive element embraces the screw member with a certain amount of play at the head end. A nut is also provided on the screw member and engages the internal walls of the insulating body, but is adapted te move along a threaded portion of the screw when the screw is rotated. The engagement of the nut with the wal1 prevents rotation of the nut. The insulating body is also provided with a conduit in at least one of its side walls, and. through this conduit an electric supply conductor may be led. from the outside of the insulating body to the interior of the assembly in a direction transverse to that of the stem of the screw member and then positioned 'between the conductive element and the nut- The insulating body is preferably closed by a lid which is permanently secured to the insulating body.

According to an alternative preferred embodiment the length of the screw is approximately equal to the spacing between the bottom of the cavty housing the head and the inner iace of the lid. The conductor may be constituted by a strip, the length of which is parallel to the length of the stem of the screw, which strip is provided with a bent over eyelet which embraces loosely the stem of the screw, the strip being introduced through a slot in the wall of the enclosure.

The advantages of the said construction are particularly apparent, when the apparatus is constructed in the form of a holder to support one of the ends of the discharge tube, more partcu1arly a low-pressure mercur-vapour d1scharge tube.

In order that the invention may be more c1early understood and readily carrid into efiect;

it will now be described more fully with reference to the accompanying drawing,n which:

Fig. 1 is a view in transversal elevation of the apparatus of invention.

Fig. 2 is a planview of the device of Fig. 1 taken on the line IIII of Fig. 1, after removal of the lid.

Fig. 3 is a view taken on Figs. 1 and 2.

Figs. 4 and. 5 are perspective views of a modified construction of the conductor shown in Fig. 1.

Fig. 6 is an. elevational view of an apparatus of the invention incorporated in a tube holder.

Fig. 7 is a rear view of the apparatus of invention and tube holder shown in Fig. 6.

Fig. 8 is a sectiorial view taken on the line VIII-VIII of Fig. 6.

As shown in Fig. 1 the apparatus comprises an insulating body l having a rectangular chamber 2 closed by a lid 3. A screw having a stem 6 is positioned in the chamber 2 and a conductive element in the shape of a metal strip 4, is provided at head end 1, of the screw. The element the line III--III of 4, is provided with an apertre 5, which is sufficiently large to permit insertion of the stem 6 of the screw thus permitting conductor 4 to loosely embrace the stem 6. The head 1 of this screw is housed in a cavty 8 provided in the bottom of the chamber 2. The screw may be turned by means of a screw-driver, which can be inserted through passageway 9 in the insulating body I. The stem 6 of the screw is furthermore provided with a square nut Ili, which is shown here in the position which it occupies during component mounting, that is to say on the narrowed, unthreaded part II of the stem of the screw. Thus nut I0 slidingly engages the walls of the chamber and cannot rotate within this chamber. The insulatng body is alsoprovided with an aperture I2 through which a conductor I3 may be introduced. 'I'his conductor is introducedin a direction transverse to the length of the stem 6 of the screw, between the conductor 4 and the nut I0.

It is evident from the above that the whole input contact is constituted by a screw, a conductive element, and a nut only. It is not necessary that the stem of the screw should comprise a narrowed part H, but component mounting is simplified thereby, as will be seen hereinafter.

When assembling the apparatus, the head 1 of the screw is first introduced into cavty 8.

The conductiveelement 4 is then slipped with its aperture 5 over the stern 6 of the screw the stem passing through the aperture 5 of the element 4 and the nut M) is then put on the end of the"stem 6; If thislend is narrowed, the nut 

